Glutathione

What does glutathione do for skin?

It is mostly sold for dark spots and a dull, uneven tone: the brown mark a breakout leaves, freckles that deepen over summer, or skin that looks grey and tired under office lights. Glutathione is an antioxidant your own cells make from three amino acids. On a label it appears as Glutathione, and sometimes in its paired, oxidized form.

The best test of it on skin is a 2014 trial in 30 healthy women aged 30 to 50. Each woman applied a 2% oxidized glutathione lotion to one side of her face and a plain lotion to the other, twice a day for 10 weeks. The glutathione side measured lighter from the early weeks to the end, and in the second half of the study it also held more moisture, had fewer new wrinkles and felt smoother. There were no marked side effects. Three of the four authors worked for the company that supplies the ingredient.

How does glutathione work on dark spots?

Reviews describe two routes. Glutathione slows tyrosinase, the enzyme that starts pigment production, and it nudges pigment cells toward making a lighter, reddish-yellow pigment instead of the dark brown one. A 2016 dermatology review puts it this way: its effects “result from direct as well as indirect inhibition of the tyrosinase enzyme and switching from eumelanin to phaeomelanin production”, eumelanin being the dark pigment and phaeomelanin the lighter one.

That explanation comes from reviews of lab work. How much of it happens when a serum sits on your face has not been measured directly.

How strong is the evidence for glutathione in skincare?

Limited. A 2025 US systematic review screened 446 articles and found only 5 clinical trials of glutathione applied to skin. Its authors wrote: “Despite its popularity, scientific research on topical glutathione is limited.” Besides the lotion trial above, one study found a 2% cream of a modified glutathione reduced redness after UV exposure.

A 2019 review that looked at tablets and lotions together reached a similar verdict: the effect “is still inconclusive due to the quality of included studies and inconsistent findings”, though there was a trend toward brighter skin on sun-exposed areas.

How long until you notice a difference?

Give it about 10 weeks. In the lotion trial, the difference in skin tone appeared in the early weeks, but the moisture and smoothness changes showed up only in the second half of the 10-week study.

How do you use glutathione?

Apply a glutathione serum or essence after cleansing and before moisturizer, once or twice a day. It often shares the bottle with vitamin C or niacinamide, so check what your other products already contain. Wear sunscreen every morning; no brightening ingredient keeps up with new sun exposure. For how this compares with other brightening options, see our guide to tranexamic acid serums for dark spots and the niacinamide entry.

Who should be careful with glutathione?

Anyone layering several brightening products at once, which raises the chance of dryness and irritation; use one and give it time. Topical glutathione was well tolerated in the trial above. Glutathione sold as injections or drips for skin lightening is a separate, medical matter: the 2016 review notes that its side effects led the Food and Drug Administration of the Philippines to issue a public warning against that use. If your skin reacts easily, patch test a new product first.